A Manual of Elementary Geology

Layers of rock and traces of earlier life become records of Earth's past in Charles Lyell's geological manual. The fourth edition, published in 1852 with 500 woodcuts, examines ancient changes through the physical evidence they have left behind. In the opening postscript, fossil footprints in sandstone prompt comparisons with living animals and careful discussion of the age of the rock. Observations from quarries and geological surveys show how new discoveries could revise existing accounts of early life.

The middle passage brings that reasoning to the scenery of the Wealden district. Lyell links valleys to softer beds and ridges or cliffs to harder stone, explaining how gradual uplift and the action of waves and currents could shape them. Chalk, greensand and clay each contribute to the landscape he describes. Readers interested in the history of geology will find a detailed example of how nineteenth-century scientists connected visible features with processes extending over long periods.